This study was devoted to investigating the performance of Unplasticized polyvinyl chloride (UPVC) pipe filled with alumina (Al2O3) and comparing with calcium carbonate (CaCO3) filler at different weight fractions. In addition to this identifying the optimum condition to extract alumina from kaolin clay was also analyzed. During extraction, the alumina was leached out by considering three factors i.e. concentration of H2SO4, time and temperature and the optimum extraction condition was obtained at 5M of H2SO4,4hr, and 80 oc, which provide about 62 % of alumina. An analysis was made to characterize or to confirm that the extracted product was the targeted alumina or not by using analytical methods such as FTIR, XRD, AAB, and TGA. The fillers were incorporated on loading ratio of 20 and 25 % into the matrix of UPVC. These composites (filled pipes) were investigated for their mechanical properties (such as ultimate tensile strength, flexural strength, impact resistance, hardness, as well as hydrostatic pressure test), thermal properties (i.e. Vicat softening, rate of change in the mass of a pipe as a function of temperature), and the. Specific gravity. From the results, it was found that there is significant improvement in mechanical properties such as impact resistance, tensile and flexural strengths with the increment of addition of filler material. When the content of alumina was increased from 20 to 25 %, the ultimate tensile strength also increased from 4.7 Mpa to 5.3Mpa. However, the ultimate tensile strength of the pipe filled with calcium carbonate was decreased from 2.78 Mpa to 1.95 Mpa when the calcium carbonate content was increased from 20 to 25 %. Additionally, the introduction of filler (Al2O3 and Ca2CO3) into the UPVC matrix results in enhancement in processing and functional properties, especially thermal stability and Vicat softening temperature. Finally, it was found that ,when the contents of alumina increased from 20 % to 25 % ,there were improvement in stiffness (2.25 to 2.32 Mpa),flexural strength (22.7 to 23.7 Mpa) ,impact resistance (3.36 KN/8cm to 4.50 KN/ 8cm) ,hydrostatic bursting time at 35.4 bar(1.43 hr. to 1.88 hr.), Vicat softening (98.30 oc to 101.11 oc),and specific gravity (1.47 to 1.5). Similarly when the calcium carbonate content increased from 20 % to 25 %, there were an improvement in stiffness (2.3 to 2.5 Mpa), flexural strength (18.08 to 19.76 Mpa), impact resistance (2.56 KN/8cm to 2.77 KN/8cm), Vicat softening (86.58 oc to 89.93 oc), and specific gravity (1.34 to 1.39),however the hydrostatic bursting time at 35.4 bar decreased from 0.18 hr. to 0.12 hr.